Inverted commas are used to express a speaker’s words written down exactly as they were spoken, which is why it has been used in this particular sentence (because the trekker said the statement). The second statement promptly starts with a capitalized word and ends with a full stop. Hence option B is the correct answer.
Option A is incorrect because inverted commas are not used to express the speaker's words in the direct speech, the second statement doesn't start with a capitalized word nor does it end with a full stop.
Option C is incorrect because the second statement neither starts with a capitalized word nor does it end with a full stop.
In option D the inverted comma is not closed after the quotation, there is no space between the words 'we are' and the statement is ending with a colon instead of a full stop.